Basal culture media used to grow human and non-human animal cells in the laboratory are typically composed of inorganic salts, buffers, glucose, amino acids and vitamins. These media are generally supplemented with animal-derived additives, most commonly fetal bovine serum (FBS), but also human serum, or other animal sera, and sometimes with extracts from other tissues. Additionally, other xenogeneic (from a species different than the cells being grown) factors are sometimes utilized to promote the growth and attachment of cells from human or non-human animal tissues. These xenogeneic supplements provide growth factors, hormones, lipids, trace elements, adhesion molecules, and uncharacterized factors, which may act alone or in concert to promote, inter alia, cell survival, cell adhesion, and cellular proliferation.
However, the use of xenogeneic animal-derived additives in cell cultures poses a number of problems for the subsequent therapeutic or clinical use of cells grown in such media. These problems include the risk of transmission of infectious agents such as mycoplasma, viruses and prions (e.g., bovine spongiform encephalopathy). Such infectious agents could pose a health risk to patients treated with cells or cell products grown in the presence of xenogeneic supplements. In addition, cells exposed to xenogeneic proteins will internalize the proteins, which can subsequently be processed and presented on the cell surface, which could result in an immune response against the cells resulting in their destruction and therapeutic failure.
Furthermore, even exposure of cells cultivated for therapeutic use to uncontaminated animal-derived supplements (e.g., sera or plasma) can be detrimental to the growth, viability, or desired behavior of cell cultures. More specifically, in the human clinical context, the serum or plasma must be matched to blood type (e.g., type A serum or plasma must be used to culture cells for use with a person with blood type A). This matching of blood type is necessary because of the presence of antibodies to the antigen not present on the donor blood cells. By way of example, plasma or serum from a blood type A person has antibodies to the blood type B antigen, and vice versa. Moreover, the present inventor is aware only of human serum being used to cultivate human cells, primarily white blood cells, in the laboratory environment. Because of its relatively high procurement cost versus its presently limited cell culture applications, human serum is prohibitively expensive for routine laboratory use.
In addition, different batches of serum, whether human or other animal, differ in their precise compositions. These variations may include but are not limited to the nature of the antibodies and hormones present in the batches which can significantly affect the behavior of cells grown in serum-containing media. For instance, for even routine laboratory cell culture use, a new lot of fetal bovine serum must be tested against old lots before purchasing the new lot in order to determine the extent of variance between the lots.
Species-matched albumin has been proposed as a basal culture medium supplement in lieu of serum or plasma. However, it is believed that albumin has been used exclusively for the cultivation of hematopoietic (or blood-forming) cells. The present inventor is aware of no prior implementations of species-matched albumin as a basal culture medium supplement for cultivation of non-hematopoietic cells suitable for therapeutic and research applications.
Thus, a need exists for a serum-free and xenogeneic product-free cell culture medium for the development of low-risk cell cultures or engineered tissues for human or veterinary therapeutic use.
A further need exists for a xenogeneic product-free cell culture medium for the development of low-risk cell cultures or engineered tissues for human or veterinary research use.
A further need exists for a cell culture medium comprising a basal medium and a supplement including a species-matched albumin for the cultivation of non-hematopoietic animal cells.